Had my first issue with the tiny 5Ah battery this weekend. The car was driven probably 150 miles on Friday and then parked at about 30% not plugged in. I went to drive it the next day maybe 14 hours later and got the spazzing dash lights, relay clicking, etc that accompany a low 12v battery.

Luckily the Tattu LifePO4 DOES have low-voltage protection, and simply turned itself off when the voltage was too low to protect itself, after charging for an hour or so all is back to normal.

I think the cooling fan and pump ran for a long time after parking it Friday (constant AC use, highway driving, and quick charging) and drained the 12v. For others less risk-adverse I would suggest at least a 10Ah LifePO4 battery, but I am still happy with the 5Ah model especially now that I know it will protect itself.

^^^ I think your right on what might have happened, 5ah isn't much capacity for running a large fan. As a backup should this happen when out and about, I might suggest a smallish portable 12v Li battery jumper. I always carry one in the back of my Leaf for just such occasions. It came with a 12v cigarette lighter adapter or small jumper cables, oh and it also has a 5v USB output for charging portable things that use USB.All in all for the <$30 I paid for it on sale, I believe $39 regular price, I hope it's worth it, if I ever ran into a weak 12v battery I bought mine at a big box hardware type of store(Menards) but I believe Amazon and other places sell similar models.

It's pretty stupid that the car had 7000wh onboard but cannot keep the 60wh 12v alive running a cooling fan for a few hours. It has been proven earlier in this thread that the OEM 12v battery really only delivers 10Ah of capacity before it can no longer support any functions. It's just plain stupid IMO, and ultimately the reason this very thread exists.

I actually have a few 4S 5000mah Lipos from an RC airplane that I keep in my cars with a modified jumper cable adapter for jump starting. I just keep it in the back at about 65% charge to maximize life and minimize fire risk and it still can deliver enough current to jump start an ICE in winter temperatures.

I was so fascinated with this thread I joined the forums just to be able to read and respond. Amazing to me that:

1) People are having this struggle with such a basic component of a much more sophisticated vehicle.2) Folks are so pationate about their arguments and battery theory knowledge.

In my former ICE hobby days, batteries were really just a disposable, if expensive, nussiance. When one went bad or wouldn't charge any more because it was sulfated or whatever, we would just haul it out and go buy another without much thought. Charging systems in European ICE cars I fiddled with just weren't that complicated, and we all learned to fight crusty ground connections first before tossing out the alternator and the like.

I'm really glad (apparently) that I have an SL with a solar cell, apparently that's good.

Anyway, pleased to be on the forum, I'm enjoying the battery discussion.

jjeff wrote:^^^ I think your right on what might have happened, 5ah isn't much capacity for running a large fan. As a backup should this happen when out and about, I might suggest a smallish portable 12v Li battery jumper. I always carry one in the back of my Leaf for just such occasions. It came with a 12v cigarette lighter adapter or small jumper cables, oh and it also has a 5v USB output for charging portable things that use USB.All in all for the <$30 I paid for it on sale, I believe $39 regular price, I hope it's worth it, if I ever ran into a weak 12v battery I bought mine at a big box hardware type of store(Menards) but I believe Amazon and other places sell similar models.

Be careful with assuming that those LiIon jump-start packs will jump-start a Leaf with a discharged 12V battery.

The ones I have used, will only output 12V for jump-starting for a second or two - because they are small, their cables are small, and the current required to crank an engine would set fire to them in a few seconds.

The Leaf will not charge a 12V battery which is very deeply discharged - for example, if the voltage is too low. I have seen this with mine when the 12V battery went bad and was down to <11V. The Leaf would "start" on the power button and drive, but the DC-DC converter stayed off, because the 12V battery "looked bad" to the Leaf's electronics.

This second or two of power from a LiIon jump-start pack is not long enough to both power-on the Leaf, and have the Leaf decide the 12V battery is good enough to charge & start charging.

VitaminJ wrote:It's pretty stupid that the car had 7000wh onboard but cannot keep the 60wh 12v alive running a cooling fan for a few hours. It has been proven earlier in this thread that the OEM 12v battery really only delivers 10Ah of capacity before it can no longer support any functions. It's just plain stupid IMO, and ultimately the reason this very thread exists.

Well two days ago I detailed my Leaf (and carpeting measurements for aftermarket special order). I was listening for the radiofor all the time in ACC mode. And had volume cranked up so I wouldn't hear the door open beeping 12V battery was supplying juice without DC-DC running. Then I went for a drive. Before doing that I took my DC-ammeter to measure current flow after switching vehicle on. Battery was sucking 30-40A. Though I had no time to measure for long.It didn't go to 13V mode for few hours though, that I was monitoring. And HV pack was discharging 700-900W while parked (LeafSpy), no AC/fan running, no radio. Only 12V battery charging happening. 14V*40A=500-600W.Well, I'm absolutely sure I drained much more than 10Ah out of that battery during those hours. 5-6 hours

Though I have 2014 Leaf. Those have different 12V algorithm than 2011/12.OEM battery. Made in the beginning of 2014.

jjeff wrote:^^^ I think your right on what might have happened, 5ah isn't much capacity for running a large fan. As a backup should this happen when out and about, I might suggest a smallish portable 12v Li battery jumper. I always carry one in the back of my Leaf for just such occasions. It came with a 12v cigarette lighter adapter or small jumper cables, oh and it also has a 5v USB output for charging portable things that use USB.All in all for the <$30 I paid for it on sale, I believe $39 regular price, I hope it's worth it, if I ever ran into a weak 12v battery I bought mine at a big box hardware type of store(Menards) but I believe Amazon and other places sell similar models.

Be careful with assuming that those LiIon jump-start packs will jump-start a Leaf with a discharged 12V battery.

The ones I have used, will only output 12V for jump-starting for a second or two - because they are small, their cables are small, and the current required to crank an engine would set fire to them in a few seconds.

The Leaf will not charge a 12V battery which is very deeply discharged - for example, if the voltage is too low. I have seen this with mine when the 12V battery went bad and was down to <11V. The Leaf would "start" on the power button and drive, but the DC-DC converter stayed off, because the 12V battery "looked bad" to the Leaf's electronics.

This second or two of power from a LiIon jump-start pack is not long enough to both power-on the Leaf, and have the Leaf decide the 12V battery is good enough to charge & start charging.

It depends upon the quality of the Li jump starter. I have used mine to start a 4.0L inline 6-cylinder, several different V-8 engines, motorcycles, and my 2015 Leaf (completely dead battery). Both of my Leafs (2011 and 2015) started just fine and recharged their 12-volt batteries after being completely discharged.

In today's 1Q conference call, Elon stated that Model Y will not use a CAN bus, and instead use a new high speed bus. He said that while Model S used 3 km of wiring, and the Model 3 uses 1.5 km of wiring, the Model Y will use 100m.

He also said they will finally discard the legacy 12V power, which he derided as saying wasn't the right voltage for anything.